Optical disk devices are highly developed information products that are widely used. They are available in many different forms such as CD-ROM, DVD-ROM and the like.
Optical disk devices have spindle motors which must be positioned precisely to keep the data carrying surface of the optical disc (CD or DVD) normal to the optical axis of the objective lens of the optical pick-up head in order to facilitate data reading and retrieval.
Conventional inclination angle adjusting mechanisms for optical disk devices can be grouped into the guide rod adjusting type that adjusts the position of a guide rod, and the spindle motor adjusting type that adjusts the spindle motor inclination angle. The guide rod adjusting type has the advantage of a smaller space in the axial direction of the spindle motor, but its drawback is the need for a longer adjusting time. The spindle motor adjusting type requires a larger space in the axial direction of the spindle motor, but can be adjusted in less time, thus is more suitable for fast assembly and adjustment in production.
In principle, to adjust the spindle motor inclination angle requires only two rotational freedom for the spindle motor. U.S. Pat. No. 6,236,636, entitled: “Spindle motor inclination angle adjusting mechanism in optical disk apparatus”, discloses a spindle motor inclination angle adjusting technique which employs three support points that are not on the same straight line to support the base dock of the spindle motor. One of the support points is fixed and serves as the fulcrum for adjusting the inclination angle. Other two support points use screws to support the base dock of the spindle motor. Adjusting the inclined angle of the base dock is accomplished by turning the two screws. When one screw is turned, the line linked between the other screw and the fulcrum becomes the rotational axis of the base dock of the spindle motor. By turning the two screws, the base dock of the spindle motor may be turned about two rotational axes to adjust the spindle motor inclination angle.
Using turning screws to adjust the spindle motor inclination angle tends to cause too large of the inclination angle at the initial installation time due to deviations of the screw positions. Using the collimator to determine the inclination angle cannot obtain the calibrating direction and results in increased calibration time, or even makes calibration impossible.